An attorney representing a man wrongfully convicted of murder today accused Brooklyn District Attorney Charles Hynes of using hotel rooms as private jails to hide away reluctant witnesses and force them into giving false testimony.

Attorney Joel Rudin – who two years ago filed a $150 million lawsuit for Jabbar Collins against the Brooklyn DA’s Office – says in a new court filing that the coercive tactic was part of widespread misconduct in the agency and was a clear violation of Constitutional protections.

Citing a deposition of a former employee who worked in Hynes’ office, Rudin says that investigators “were trained to bring material witnesses directly to the DA’ s Office, instead of to court, for investigative questioning, and they would later be held against their will at hotels.”

“Hynes’s office was running a private jail system where witnesses were illegally interrogated and forcibly detained indefinitely,” Rudin wrote to a federal judge.

Today’s explosive new allegation expands upon a wide-range of similar charges Collins made two years ago in his federal civil rights lawsuit, where he says such illegal tactics played a central role in his wrongful conviction.

Collins’ suit charged that a rogue prosecutor in the DA’s Office “would gain the involuntary custody of witnesses from which he would coerce false statements and testimony” – often using unethical methods to secure a court order sanctioning the detention.

Collins – who served 15 years in prison for a murder he later was cleared of committing – has accused Hynes of turning a blind eye to his investigators’ misconduct during the high-profile probe into the killing of Rabbi Abraham Pollack in Williamsburg during a 1995 armed robbery.

His civil rights lawsuit claims that two key prosecution witnesses in the murder case against him were bullied using these exact methods – the use of coerced witness testimony achieved by illegally holding people as material witnesses and hiding them away in facilities not routinely used to house detainees in Brooklyn criminal investigations.

One such person was Angel Santos, who later told a federal judge that he had been threatened by Rackets Bureau Chief Michael Vecchione in the Brooklyn DA’s Office after he balked at taking the witness stand at Collins’ murder trial.

“He told me he was going to hit me over the head with a coffee table or lock me up for a couple of years for perjury,” Santos a federal judge at a 2010 court hearing.

Collins’ lawsuit charged that Santos was “unlawfully imprisoned” as “a material witness,” and threatened with physical harm if he did not testify as directed.

“Santos was locked behind bars at the Bronx House of Detention, housed with accused criminals, for more than a week,” Collins lawsuit charges.

Another witness in the Collins’ murder prosecution, Edwin Olivia, also was coerced into becoming a prosecution witness and hidden away in an upstate jail, Collins’ lawsuit claimed.

“Oliva was sent to Ulster Correctional Facilty. He was informed that he would remain imprisoned upstate until he agreed to ‘cooperate’ with the DA’s Office,” Collins says in his 2011 lawsuit.

Two weeks ago, Collins’ attorney’s wrote to a federal judge overseeing the civil rights case and complained that Hynes was refusing to hand over evidence about “material witnesses held in ‘Hotel Custody’ and/or against their will.”

Rudin has asked Brooklyn federal Judge Frederic Block to order the DA’s Office to produce these materials – and a wealth of other information – as part of the mandatory evidence exchange process that precedes a civil trial.

The judge has not yet ruled on the issue, but Hynes’ office has argued that some of this material is private and cannot be released. Several sealed court hearings have focused on this struggle over evidence in Collins’ federal civil rights case.

At a court hearing about the case last year, Block slammed Hynes and sharply criticized the longtime prosecutor for turning a blind eye to misconduct claims.

Jerry Schmetterer, a spokesman for the Brooklyn DA’s Office, said the agency had committed no wrongdoing. “It is not – nor was it ever – the practice of this office to hold people in hotel rooms against their will without judicial intervention,” Schmetterer said.

Arthur Larkin, an attorney for the city – which represents the DA’s Office in the Collins’ civil case – said the charge was ludicrous. “Mr. Rudin’s hyperbolic characterizations of various alleged practices in the Brooklyn DA’s Office are irresponsible and absurd,” Larkin said.

Block said that he was deeply troubled by Hynes’ inaction after another federal judge overturned Collins conviction in 2010 and accused the DA’s Office of outright misconduct in their manipulation of evidence and witnesses in the case.

Block suggested that Hynes – who is now up for reelection – had failed to take steps to curb Vecchione, who has been accused of being a rogue prosecutor.

The judge went on to vow that during the course of the upcoming Collins’ federal civil rights trial that “all of this is going to be uncovered,” referring to the alleged misconduct claims.

“Some of these allegations seem very credible,” Block said of the Collins claims.